I don't think there's a precise threshold, but when I use the phrase "change the world", I'm pretty confident that my interlocutor is thinking of people like Steve Jobs and companies like Apple and not thinking of people like me who don't have our own wikipedia articles and companies like the ones I work for that don't have names many would recognize and aren't credited with inventing/popularizing important product categories that millions of people now use every day.

People who "change the world" make big political, technological, or scientific changes and bring them into the lives of many people.